I disagree. Delta built their reputation on great service. Delta still does a lot of little things very well.

I maybe get one international upgrade to D1 every couple of years. My experience is that you can have as much or as little service as you want. For example, I was on a DCA-ATL-CDG-BUD itinerary in late 2014, and was able to upgrade the TATL portion with miles. That day, I had started work at 0500 and by the time they closed the door on ATL-CDG it was 1530. I was exhausted, and right at wheels up I put the seat into the supine position and slept probably 5 hours. The FAs left me alone, and I had a really good nap. When I woke up, the FA noticed me and came over to check on me. She then provided me with all the small plates that they had on the flight (I passed on the entrée). She made sure my drink glass was full, and generally took wonderful care of me. This was great service; far more than the minimum they could do for you.

I'm happy flying on AF, but I have noticed that, after working quite hard for 90-120 minutes while food and beverage service are going on, the crew disappears until breakfast. They leave a bottle of scotch and a couple of bottles of wine/champagne on a buffet, along with some soft drinks in a fridge and some snacks, and that's it. Delta's service is continuous through the night; if you need something, one of the FAs, even assigned to Y, will come and get it for you. Virgin Atlantic's FAs have a certain style and flair, but I'm not sure that they do more for you than what Delta does for you.

I'd love to go on Singapore or Cathay sometime, but that will probably be in another lifetime.